This invention relates to change making and more particularly to a change making system for a money handler in a vendor.
Conventional coin handling and change making systems detect if a predetermined number of the lowest denomination coins are available in the change bank. For example, if nickels are the lowest denomination coins in a particular change bank, the predetermined number will typically be four. With this many nickels, change can be returned when a quarter is used to buy a five-cent item or service. When the supply of nickels is less than this predetermined amount, the system automatically switches to a "correct change only" mode in which it permits a vend only when the amount of money deposited equals the selling price of the article to be purchased. For instance, in these conventional systems a vend requiring ten-cents change is not permitted, even though the change bank contains a supply of dimes, so long as the supply of nickels is depleted, i.e., so long as the change bank does not have at least the predetermined number of nickels available.
The limitations of these conventional systems become even more apparent when more than two denominations of coins are stored in the change bank. For example, a significant number of the lowest denomination coins must be stored in the change bank to satisfy the change payback requirements of the conventional systems even when change can be made using the available larger denomination coins.
There is at least one coin handler that avoids some of the problems outlined above by sensing minimum coin levels in more than a single change tube. This handler, however, has additional deficiencies that could be improved. For example, if this handler is to return 30.cent. in change, it will return dimes until the level of dimes falls below the minimum-dime level, at which point it will start to return nickels to complete the returning of change--even if there are no nickels in the nickel change tube. Thus, the customer on occasion can be shortchanged using this system. Although this system does return change in many circumstances when other conventional change making systems will not, it will not always return change whenever there is some combination of coins available in the change tubes to make the desired amount of change. For instance, if quarters and dimes are available, but nickels are not, this system will not make 40.cent. change even though change could be returned using four dimes. An additional disadvantage of this coin handling system is that it will return an amount of change, e.g., 30.cent., which is larger than the largest denomination coin deposited, e.g., a quarter. This condition, which occurs when the handler is being misused as a change maker, is undesirable and should be prevented.
Additionally, conventional systems would be especially handicapped if the government were to introduce a coin of a denomination which is not divisible into or by the value of other coins used in making change, e.g., a two-cent coin. For example, if thirteen cents (13.cent.) were to be returned to a customer from a change bank containing only 2.cent. coins, nickels and dimes, conventional coin systems would be unable to return change. These systems would begin change return with one dime and then be unable to complete the return of change, even though change could have been made using a nickel and four two cent coins. This situation also occurs in various foreign countries.